<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <style>
    * {
      margin: 0;
      padding: 0;
    }
    .container {
      width: 750px;
      margin: 0 auto;
    }

    .container ul {
      display: flex;
      flex-wrap: wrap;
      list-style: none;
    }

    .container ul li {
      width: 93.75px;
      height: 30px;
      background-color: green;
      color: white;
    }

    @media screen and (max-width: 768px) {
      .container {
        width: 100%;
      }
      .container ul li {
        width: 33.33%;
      }
    }
  </style>
  <body>
    <div class="container">
      <ul>
        <li>导航栏</li>
        <li>导航栏</li>
        <li>导航栏</li>
        <li>导航栏</li>
        <li>导航栏</li>
        <li>导航栏</li>
        <li>导航栏</li>
        <li>导航栏</li>
      </ul>
    </div>
  </body>
</html>
